1. Field of the Invention
The present invention relates to an optical lens, a lens unit, an imaging module, an electronic device, an optical lens production method, a lens mold, and a shape correction method for the lens mold.
2. Description of the Related Art
Generally, when an optical lens as a molded article is produced using a lens mold produced on the basis of prescribed lens design values, a shape of the molded optical lens is not necessarily the same as that based on the lens design values. The reason for this is that the lens shape is affected by stress caused by a molding shape or shrinkage of the material itself in the course of cooling of the molded article. Accordingly, when an optical lens of which a shape is the same as that based on the lens design values is intended to be molded, the optical lens is molded using a lens mold, thereafter the shape of the molded optical lens is measured, and correction processing for making the lens mold have an appropriate shape on the basis of the measurement results is performed. For example, in the descriptions of JP1996-216272A (JP-H08-216272A) and JP3973430B, a marking is provided outside a lens effective portion of the lens mold, a surface shape of a molded lens article onto which the marking is transcribed is measured, shape errors, which are differences between design values and the measured values of the surface shape, are calculated, and the shape of the lens mold is corrected on the basis of the information about the shape errors.
In the description of WO2005/115712A, a molded lens article having a transcriptional mark onto which a marking is transcribed is tentatively molded using a lens mold for test with a marking having a concave shape, a curved lens surface shape is measured using the transcriptional mark of the molded lens article, correction information is calculated from the measured curved lens surface shape, and a lens mold actually used is produced again.